The present invention relates to a semiconductor device and a power supply device using the same, and in particular to a technology effective when applied to a switching power supply device equipped with a power factor correction circuit.
A technology which controls a pulse width of a switch using a square circuit and an adder to reduce a distortion rate of an input current in a switching power supply device based on an input electrolytic capacitor-less one converter system, has been described in, for example, a patent document 1.    [Patent document 1] Japanese Unexamined Patent Publication No. 2002-300780.